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4Sheets--Sheet1. W. O. LOGKWOOD. Telephone.

No. 233,360. Patented Oct. 19,1880.

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Telephone.

No. 233,360. Patented Oct. 19,1880.

MPETERS, PHOTOLITHDGRAPHER, WASHINGTON D C W. C. LOCKWOOD. 4Sheets--Sheet3 Telephone.

No. 233,360. Qatented Oct.19 ,1880.

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gfitw Cowg @WWIO N PETERS. PHDTO-UTMOGRAFHEE WASHINGTON, D 04 UNITED STATES PATENT OFFICE.

WILLIAM C. LOCKWOOD, OF CHICAGO, ILLINOIS, ASSIGNOR TO LOCKWOOD TELEPHONE COMPANY, OF SAME PLACE.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 233,360, dated October 19, 1880,

Application filed January 27, 1880.

To all whom it may concern:

Be it known that I, WILLIAM O.Looxwoon, of Chicago, Illinois, have invented a new and useful Improvement in Telephones, of which the following is a specification.

The invention consists in a magnet made adjustable in two paper chambers toward and from the diaphragm, a combination diaphragm, and a soft-metal mouth -piece, and also the means shown for intensifying the power of the magnet, all of which is hereinafter more particularly described and shown, reference being made to the accompanying drawings, in which- Figure l is a perspective, showing the top and front of the box and magnet-chambers in which the parts are arranged. Fig. 2 is a rear view of the same, a part of the outer box being removed. Fig. 3 is a longitudinal horizontal section on the line w :10, Fig. 2, and Fig. 4 is a longitudinal vertical section on the line w m. Fig. 3.

Like letters of reference indicate like parts in the several figures of the drawings.

A is the outer box, which may be made of wood most conveniently. A is a cylindrical chamber, made of paper, and having attached at the front end the smaller cylindrical chamber A extending beyond the box A.

E is astraight magnet, which passes through the chambers A A and is provided with electric wire coils or spools E E of the usual construction, and rubber spring F, rubber packing F, and a screw-thread with the nut G at the rear end. By means of the screw and nut and the rubber spring the magnet may be adjusted toward or from the diaphragm.

B is the mouth-piece, made of soft metal that is, cast or malleable iron not hardened in any way, that being the best metal for containing or affecting magnetism. The object and eflect of such mouth-piece arranged outside of a telephone-diaphragm is to extend or increase the magnetic attraction or influence outside of the diaphragm, and thereby affect the action of the magnet upon the diaphragm in an increased degree, makm g the diaphragm more sensitive to the sound of the voice, and so giving a louder and firmer tone to the instrument. I have ascertained by experiment that such metal mouth-piece so placed produces the result stated.

The diaphragm is formed of a silver plate, C, having a circular openingin the center, and a mica plate, D, located just behind the plate C. Between the plates 0 and D and the plate C and soft-metal mouth-piece B are placed rubber or insulating rings C, to prevent the contact of said plates with each other and with the mouth-piece.

A A are cylindrical chambers, made of paper, and located just outside and on opposite sides of the chamber A and partially within the box A. These chambers A A contain wire coils or spools E E and the space between the spools and circular walls of these chambers is filled with mixed ground emery and magnetized iron filings.

H H. H H are the wires running from the spools E E E E of which H H connect the spool E to the rearof thechamberA by means of screw-pegs h it, (see Fig. 2,) one of these two wires being extended from its peg to the ground and the other being connected to the transmitting-line, and H H are extended out from the spools E E and connected with a battery of the usual construction. (Not shown.)

By means of the spools and their connections the power of the magnet is increased at least fourfold, and the paper chambers in which the magnet is inclosed are highly sonorous.

The diaphragm formed of the silver plate, with its opening and the mica plate arranged as shown, is exceedingly sensitive to vibrations or air-waves, and the magnet is made adj ustable backward or forward to the diaphragm, for the purpose of adapting the instrument to the various changes of atmosphere and circumstances to which its use at different times and in different localities may subject it, and the whole arrangement of the parts is intended to secure the best results.

Having thus described my invention, what 1 claim, and desire to secure by Letters Patent, is

1. The magnet E, passing through paper chambers A A and made adjustable in the direction of its length by means of the rubber spring F and thumb-screw G, substantially as and for the purpose specified.

2. In a telephone, the diaphragm composed 4. In a telephone. the combination of a magof the open silver plate 0 and mica plate D, net, E, with coils E E E E connected and 10 insulated by ring 0, substantially as and for inclosed in paper chambers, substantially as the purpose specified. and for the purpose specified.

3. In combination with the diaphragm of a WILLIAM G. LOOKWOOD. telephone, the soft-metal mouth-piece B, iusu- Witnesses: lated from the diaphragm by a ring, 0, sub- J. W. MERRIAM, stantially as and for the purpose specified. JAMES CAMERON. 1 

